Does scheduled downtime affect OEE?
OEE (overall equipment effectiveness) is a metric used by manufacturers to determine the overall efficiency of their machines. Manufacturers often wonder how scheduled downtime affects OEE since downtime can be a reflection of production inefficiency. In reality, unplanned downtime has the greatest negative impact on manufacturing efficiency and should be reflected in how OEE is measured.
If downtime is unplanned or unscheduled that means that one part of a production line, machine cell, or even an individual machine, is operating outside of the business’s planned manufacturing process.
Below, I will highlight a few of the nuances of this subject and highlight how manufacturers need to consider downtime when calculating OEE.
How do you conduct downtime analysis and calculate scheduled downtime?
Keeping downtime analysis focused on unplanned instances gives manufacturers better visibility into what their potential production efficiency looks like.
Knowing when the machines are up and when they are down is paramount to being able to understand how well you are producing to plan. It also helps you see the amount of waste (financial, product, you name it) that occurs inside the manufacturing process as well.
“Are we missing something that is causing us to waste time and money”?
Being able to parse through the nuances of your downtime will give you a much greater level of understanding in what you really want to know… “Are we missing something that is causing us to waste time and money”?
If you’re managing your company on an OEE number or an availability number, marking downtime as planned doesn’t point out the fact that you could actually run when a machine is not scheduled.
What is an example of monitoring downtime and calculating OEE?
EXPERIMENT YOURSELF: Try our free OEE calculator to enter some unplanned downtime into the unplanned downtime field. Then, look at the availability number. Next, take out that unplanned downtime and look at the availability number, you’ll see how it potentially hides the additional time you could be running.
How should I look at OEE and downtime loss?
Being able to see how the machines are running, and how production lines and planned processes are executing according to the schedule/process/plan, will provide insights for every manufacturer that are unique.
Manufacturers with strong factory floor visibility can quickly identify error codes or machine issues as they happen and can address issues before the time for ROI is lost.
Being able to look at OEE in a granular fashion opens up your ability to impact overall performance to a much greater degree on the factory floor. This is true for real-time issues with machines and systemic issues that may be the result of operational practices that are typically unseen.
OEE is not a magic number that every manufacturer should simply optimize around to achieve the best possible results. The number itself is arbitrary to the relative improvements each individual manufacturer can make. Let me explain a little bit more…
What is the real reason for OEE downtime loss?
Unplanned downtime directly impacts one of the core measurements of OEE, availability.
Availability represents how much time a machine can run. It should include planned and unplanned maintenance, waiting, changeovers and lack of supply. Using reason codes to track downtime, companies can determine root causes and develop corrective actions to stop these issues from occurring in the future.
The problem is when manufacturers have unplanned downtime that can’t be accounted for or explained. This can make availability worse, or inaccurate. Both are bad.
What’s more, unplanned downtime that cannot be tracked, explained, or measured properly can affect the other components that make up OEE as well, performance and quality. This means that the ability to accurately understand and account for unplanned downtime is paramount in understanding your true OEE.
There’s not really a good or bad OEE, just one that is relative to your business. The real power comes in having an OEE number that accurately represents how your shop floor is running when everything is accounted for.
Having this kind of insight into your downtime will provide manufacturers with a clear picture of ROI once they correct systemic issues. The improvements in an OEE number can be quantified to a much better degree once you have all the machine data that matters.
What OEE downtime model is best?
If you want to know if you should measure scheduled downtime when calculating OEE the answer is, yes. But, that isn’t as important as being able to accurately account for all downtime, planned and unplanned. Understanding how downtime actually impacts machine availability will offer far better ROI in the long term and will provide a much more accurate and actionable OEE number for your business.
If you have additional questions about calculating OEE, leave them below and a member of our team will answer. Additionally, if you’re interested in calculating OEE, you can use our free calculator or cycle time formulas here.
Lastly, if you want to better understand when the machines are up, when they are down, and why (really, why). Check out SensrTRx LEAN. It’s an affordable way to see all of that information that is very affordable and can be set up by internal staff in just a few hours.